(1) The conveyance of a non-freehold interest in land. (2) The instrument by which a leasehold or working interest is created in minerals. The oil and gas lease has passed through an evolutionary development. Early leases were generally for long terms without a THEREAFTER CLAUSE. Another early form of the lease was the NO-TERM LEASE. Most contemporary leases are of the Unless or Or types [See OR LEASE; UNLESS LEASE). The very name, ”lease,” is unfortunate as it tends to give the impression to the uninformed that the “oil and gas lease” is of the same genus as the common law “lease” of land, whereas, except in Louisiana the dissimilarities are more important than the similarities. The most common oil and gas lease in the mid-continent area is the so-called ”Producers 88″ lease. [See 88 LEASE].